Benjamin Zander is the conductor of the Boston Philharmonic Orchestra and an inspiring public speaker. He believes that everyone can love and appreciate classical music. If you have any spare time this week, please, please, please watch this short talk he gave at a TED conference in 2008: http://www.ted.com/talks/lang/en/benjamin_zander_on_music_and_passion.html. It is informative, funny and, in the end, moving.
One of the points that Benjamin Zander makes is that the things that we say can have much more significance than we imagine at the time. This applies especially to the kinds of things that people say to children. How vividly we remember certain things that were said to us, both positive and negative, which deeply affect our self-image and the paths we take for the rest of our lives. How many of us, for example, believe in our deepest souls that we cannot sing, or do maths, simply because an influential figure told us so in our formative years?
So as parents we need to take care about exactly what we say to our children, and how, and when, we may tell them things. In the field of learning about and learning how to play music, this is no less true. A parent's opinion given at a critical moment has the potential to do great damage or great good. And as we aren't easily able to predict when those critical moments may occur, it is the wise parent that is, as far as possible, always conscious of what exactly they are saying to their child, and how they are saying it.
Of course, it's important to praise your child's efforts. This is one of the rewards that they (and, let's face it, most of us) are willing to work for. Simple praise (Well done! That was great!) is good, but meaningful praise is better. Meaningful praise refers to the actual content of the effort, identifying and highlighting to the child the things that went well: Wow, you played all the notes correctly that time! It should be possible to always find something that went well, even if it's only the fact that the child sat on the stool!
Without thinking about how to improve playing, though, there can be no progress, so you may also want to point out to your child things that could get even better. The best way to do this is to encourage the child to listen to and reflect on their own playing, then the motivation to improve comes from within and is not something that is being imposed. One way that my son and I do this is to write out a small grid of points to remember, such as playing with a soft left hand, then after each piece he can tick which he thinks he did. It's important not to overwhelm a child with several things they should try to focus on all at once, though. One or two is enough.
As adults we sometimes have the habit of saying things, especially negative things, indirectly, but I think it's important to remember when speaking to children that adults have a large linguistic advantage. We've been using the language much longer, have a wider vocabulary, and understand how to manipulate meaning into sarcasm, irony, implication and insinuation with ease. Children can be confused by such use of language, or completely miss the point of what they're being told. This is why I believe it's always best to be clear and direct with them. It is fairer and your statements are easier for them to understand.
Words are important, but equally so is their absence. Sometimes, when we're having a bad day, and my son is grumpy about practising, tempers may start to flare. I've found in these circumstances that often the best response is silence. Maybe the thing that was said was not really meant, and simply not replying allows the speaker time and space to consider their words. I don't mean a resentful silence, but a calm and pleasant acknowledgement without reply. Some things do not need to be answered.
Similarly, silence on the part of the parent gives the child a space to speak into. There is no need to feel uncomfortable about silence and always fill it with your own voice. Maybe it takes your child a while to formulate their thoughts. Children need a silence to play into and to reflect in at the end of their playing, as well.
In short, I think that as we ask our children to listen to their playing, we should also be listening to ourselves responding to them. This way we can then be truly supporting our children and not hindering their growth. We will also be providing a good model to them. Not only will they be learning to play an instrument, they will also be learning how to speak respectfully and thoughtfully to others.